Determination and Degradation Study of Enalapril Maleate by High Performance Liquid Chromatography

Abstract

Enalapril maleate belongs to the group angiotensin-converting enzyme inhibitors used in the treatment of hypertension and heart failure. In this work, reversed-phase high-performance liquid chromatography (RP-HPLC) method for the determining the level of impurities in enalapril maleate tablets was developed and validated. A Snyder triangle was approved for the optimization of RP-HPLC separation of enalapril in the presence of five impurities and two degradation products. Separation was achieved on an octadecyl silica column using a mobile phase of 20 mM phosphate buffer (pH 2) – methanol – THF – TEA (66 : 25 : 9 : 0.1, v/v) with UV detection at 215 nm. The degree of linearity and the characteristic statistical parameters of calibration curves, including the limit of detection (LOD) and limit of quantitation (LOQ), for Enalapril maleate and its degradation products were estimated. The method was found to be specific, accurate, and precise. The stability indicating capability of the assay was proved by conducting a test under forced degradation conditions of temperature and humidity on a commercial drug product.